1. Field of the Invention
Embodiments of the present invention relate at least to the compensation of phosphor persistence, and more particularly at least to a method, medium, and apparatus compensating for differences in persistence of phosphors in a display panel and a display apparatus, medium, and method displaying video data compensated for differences in persistence produced by phosphors having different response times.
2. Description of the Related Art
Recently, with the growing interest in high definition television (HDTV), development has been very active in display panels such as liquid crystal displays (LCD), plasma display panels (PDP) and organic light emitting diodes (OLED), for example.
Unlike conventional display devices, display panels, for example, are light and thin, and thus may be applied to various fields including televisions, computers, camcorders, automatic navigation systems, etc., and are therefore represent an important technology.
However, in such a display, typically phosphors emit light through three different light-emitting materials corresponding red (R), green (G), and blue (B). However, these respective phosphors have different response times, which results in phosphor persistence occurring in the front and rear of moving objects on a display screen.
For example, when a bright object moves against a dark background, color persistence occurs in front of and behind a moving object.
This phenomenon will now be explained in more detail.
FIG. 1 illustrates response times of different conventional phosphors that emit light corresponding to red (R), green (G), and blue (B) (hereinafter referred to as a “red phosphor”, “green phosphor”, and “blue phosphor”).
As illustrated in FIG. 1, the green phosphor has the lowest (slowest) response time, the blue phosphor has the highest (fastest) response time, and the red phosphor has a response time that is intermediate of the two response times.
For example, as illustrated in FIG. 2, if a white object with a black background, in a frame I(n−1)(201), moves in a horizontal direction in a subsequent frame I(n)(202), an edge with a mixture of blue and red occurs in front of the moving object and a phosphor persistence with a mixture of green and red occurs behind the object.
In order to prevent this phenomenon, for example, U.S. patent application Ser. No. 2004-0169732, discusses selecting video data for the R and B light-emitting elements, which have response times that are different from the longest response time, e.g., from a G light-emitting element, and compensating video data the R and B light-emitting elements so that the difference between the response times of the R and B light-emitting elements are artificially compensated for in view of the expected response time of the G light-emitting element.
Specifically, here the discussed method includes modifying the differences in persistence of phosphors between light-emitting elements by adding a predefined quantity of persistence to the R and B phosphors, having short response times, based on the G phosphor having the longest response time. This method uses an exemplary non-linearly decreasing function given by the below Equation (1), as a coloring mode.
                              Corr          ⁡                      (            x            )                          =                                                            B                n                            -                              B                                  n                  +                  1                                                      255                    *          a          *                      B            n                    *                      ⅇ                                          -                b                            *              x              *              v                                                          (        1        )            
Here, x denotes a pixel position in the persistence, v the length of a motion vector, Bn a video value of a blue component at the current pixel position, Bn+1 a video value of a blue component at the position of a neighboring pixel, and a and b are adjustment constants.
However, according to this conventional technique, only the red phosphor and the blue phosphor, which have relatively short light-emitting times, are modified. However, if the motion is fast, a severe motion blur occurs due to the compensation of the red phosphor and the blue phosphor. In addition, when implementing such a persistence compensation using a non-linear function, using motion vectors as a parameter in the form of a lookup table (LUT), the size of the LUT would be very large to maximize performance. Embodiments of the present invention overcome these drawbacks.